Portable power unit



Jan. 16, 1951 w. M. SHOFFNER PORTABLE POWER UNIT Filed Aug. 6, 1948 INVENTOR WILLIE M. SHOFFNER Patented Jan. 16, 1951 UNITED STATES PATENT OFFICE Willie M. Shofiner, Dayton, Ohio Applieationdugnst 6, 1948-, Serial-N0. 42,960

4 Claims. 1

This invention relates to aportable power unit adapted for placement on a: bench for driving variousmachinetools.

An-object of the invention is to provide aportable power unit that can be placed on abench for. driving variousmachine tools, such as tools for forming sheet metal.

It isstill another object ofthe invention to construct the portable power unit in such a manner that it will be solidly supported on a bench regardless of minor irregularities that develop inthe tops of Work-benches. n

Further objects and advantages will become apparent from the drawings and the following description.

In the drawings:

Figure l is a perspective elevational view of the portable power unit of this invention;

Figure 2 is a perspective elevatic-nal view'of the portable power unit taken from the side thereof opposite to that of Figure 1';

Figure 3 is a cross-sectional view taken along line 3-3 of Figure-2;

Figure 4 is a cross-sectional view of the construction of the motor mounting.

In this invention the portable power unit consists of a frame Ill that is composed of a pair of angle members ll and i2 positioned substantially parallel to each other. The angle members ii and I2, or side rails, are connected together at one end thereof by means of the cross-rail or angle member 53. The opposite ends of the side rails H and I2 are connected together by means of an angle member It that has a flange i5 thereof depending below the bottom surfaces l6 and H of the angle members ll and i2, respectively. A clamp pad 98 extends between the side rails I! and i2 adjacent the front end thereof and adjacent the angle member 5 3. The siderails H and I2 are each provided with an arch from front to rear thereof, as can be seen by reference of the rail l2 to the dot-dash line 20. The rear connecting rail is is also provided with an arch between the ends thereof as can be seen by reference to the dot-dash line 2 l.

The arch provided in the side-rails H and E2 and in the rear rail l3 provides an arrangement whereby the frame I!) will be supported on a horizontal surface by the ends of the rails ll, l2 and I3. Thus,irregularities in the surface of a Work-table or bench will not affect the stability of support of the power unit on a work-table.

At one end of the frame it there is provided a metal box 25 that has open sides 25a and 26a. The box is provided with a bottom wall 25 that is 2, suitably flanged so that the box can; be bolted between. the side-railsv ii and [2 by means of bolts 2-? An electric motor 28'is supported upon the, bottom wall 26 of the box 25 and a speed red'ucing unit 25 is. supported on the upper wall 30 of the boX 25.

The electric motor 28 is supported on the wall 25 by means of the bolts 3| and the resilient support bushings 32. The support bushings 32 are of a rubber-like material to pIOVlde for flexibility in the motor. mount. A guide-pin 33 passes through an opening 3 3 in th base 35 for the motor 28 to prevent side sway of the motor.

The speed-reducing unit 29 is bolted to the box 25 in conventional manner.

The motor 28 and the speed-reducer 29 each have a multiple speed pulley on the respective drive shafts, such as pulleys 35 and 31 with a belt 38 extending therebetween. I

The resilient mounting'of the motor 28 provides for automatic belt tightening of the belt 38.

The output shaft of the speed-reducer 29 is connected to a telescoping power shaft 416- of a type disclosed in my copending application, Serial No. 781,961, filed October 24, 19h. This power shaft 'fl consists generall of a universal joint M at one end thereof that connects, to the output shaft of the speed reducer 29 and a universal joint 42 that is adapted to be connected to a machine for driving the same. A telescoping shaft 33 is provided between the universal joints 4! and $2 to take care of varying distances between machines that are to be driven by the portable power unit.

A support bracket 5i! is secured between the side-rails H and i2 of the frame it and is provided with a socket 51 which receives the power shaft lt to support the same when the device is not in use, and to prevent damage to the universal joint 52 in the event the power unit should accidentally be started while the power shaft is not connected to a machine.

The electric motor 28 is controlled by a footswitch 55a for starting, stopping or reversing the action of the electric motor 28 which is of the type that can be operated in either direction of rotation.

A flexible electric cord 5i is provided for connecting the power unit with a suitable source of electric current.

From the foregoing description, it will be apparent that the power unit can be placed on a work-bench with the flange l5 against an edge of the bench. Thus, when the telescoping power 3 shaft 40, which is extended by means of a coil spring contained in it, is connected to a machine set on the bench or in front of the bench, the

power unit will not slide rearwardly of the bench away from the machine to be driven. Also, a non-rocking support is provided for the power unit since the arched rail members H, l2 and I3 will rise above the horizontal plane formed by the top of the bench to avoid engagement with minor irregularities on the surface of the workbench.

A control switch 55 can be provided for controllin the flow of electric current to the footswitch 50a.

While the apparatus disclosed and described herein constitutes a preferred form of the invention, yet it can be altered mechanically without departing from the spirit of the invention, and it is understood that those modifications that fall within the scope of the appended claims are intended to be included herein.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A portable power unit comprising, a pair of frame members positioned side by side but in spaced relationship, said frame members having their lower surfaces formed in an arch relative to a horizontal plane, a frame member extending transversely between said pair of frame members at one end thereof, a second frame member extending transversely between said pair of frame members at the opposite end thereof and having a flange portion thereof depending below the arched surfaces of said pair of frame members, and a source of power carried by said pair of frame members at one end thereof opposite to said second transverse frame member.

2. A base for a portable power unit comprising, a pair of frame members positioned side by side but in spaced relationship, said frame members having their lower surfaces formed in an arch relative to a horizontal plane, a frame member extending transversely between said pair of frame members at one end thereof, said frame member having the lower surface thereof arched between opposite ends of the member, a second frame member extending transversely between said pair of frame members at the opposite end thereof and having a flange portion thereof depending below the arched surfaces of said pair of frame members, said pair of frame members being adapted for supporting a power unit thereon at the end thereof opposite to said second transverse frame member.

3. In combination; a power unit and a base therefor especially adapted for bench mounting, said base comprising longitudinally and transversely extending frame members connected together, and at least some of said members being arched upwardly between their points of connection with the other members to provide spaced points of contact of said base with a bench top.

4. In a base for supporting a power unit; angle members forming side and end rails connected together adjacent their ends, the side rails and one end rail having their vertical flanges extendin upwardly and being arched upwardly between their ends, and the ther end rail having its vertical flange extending downwardly, said upwardly arched rails providing spaced points of contact of the base on a bench top, and the vertical flange on the said other end rail providing means to abut the side edge of a bench top, and means on the base adjacent the said one end member for supporting a power unit.

WILLIE M. SHOFFNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,593,783 Stresan July 27, 1926 1,741,561 Erisman Dec. 31, 1929 2,097,729 Mall Nov. 2, 1937 2,242,722 Henry May 20, 1941 2,386,463 Hile Oct. 9, 1945 2,437,717 Werner Mar. 16, 1948 2,454,538 Bazley et al Nov. 23, 1948 FOREIGN PATENTS Number Country Date 674,428 France Jan. 28, 1930 

